To permanently remove hair from a living being, it is necessary to stop hair growth at its source, the papilla located at the base of the hair follicle (a tubular aperture in the skin). It is known that an electric current applied to the papilla will coagulate it, and thus prevent it from initiating new growth. Conventional methods for applying the electric current are not reliable and often lead to painful burning of the skin and possible scarring. Two methods are presently in wide use. The oldest is referred to as electrolysis. In electrolysis, an attempt is made to precisely insert a thin needle into the individual hair follicle to the depth of the papilla, and a controlled RF voltage, sometimes as high as 200 volts, is applied. Skill is needed to properly locate the papilla, and improper needle insertion can be painful. Furthermore, some persons have curved or spiral hair follicles, making it especially difficult to locate the papilla.
The other conventional method, first disclosed in the Fozzard U.S. Pat. No. 2,888,927, replaces the needle with a tweezer which grasps the hair above the skin. A high RF voltage up to 800 volts is then applied for a period of 6 to 45 seconds. At the end of this time, the hair is supposed to release and slide out. Hair is not a good conductor of electricity, and thus it has been surmised that the method relies on capacitive coupling between the tweezers and the papilla. In practice, the method is less than 50 percent effective, and success seems to depend on the properties of the hair being removed.
Both conventional methods are time consuming and potentially painful should their high voltages be wrongly applied.